The invention relates to a magnetic position sensor, consisting of a dielectric and nonmagnetic support carrying a resistive layer in addition to a contact layer spaced from and at least partially overlying the resistive layer, the spacing being such that contact is made between the two layers by a magnet that can be moved along the overlying regions of the resistive layer and the contact layer.
Position sensors detecting the position of an element relative to a reference position are generally known. An example of such a position sensor is disclosed in DE 43 39 931. However, this position sensor has the disadvantage that it operates mechanically under pressure such that the position sensor is subjected to a high degree of wear and tear.
In order to reduce the wear effect, magnetic position sensors have been known, such as from DE 196 48 539 [U.S. Pat. No. 6,070,337] or DE 10 2004 004 102 [US 2007/0152658].
A generic, passive magnetic position sensor is known from DE 195 26 254 [U.S. Pat. No. 5,798,640]. This position sensor consists of a dielectric and nonmagnetic support carrying a resistive layer in addition to a contact layer spaced from and at least partially overlying the resistive layer. The contact layer is a bending beam structure shaped like a meander and mounted between two spacers. The spacing between the contact layer and the resistive layer is selected such that with the effect of a magnet, in this case a permanent magnet that can be moved along the overlying regions of the resistive layer and the contact layer, contact is created between the resistive layer and the contact layer, thus resulting in a detectable change of resistance upon application of an electric current on the resistive layer that represents a measure of the relative position of the permanent magnet with respect to the position sensor.
Although such a sensor will reduce the wear effects to a minimum, it is still disadvantageous with regard to the extensive construction thereof, since the contact layer can be produced only at great effort in the shape of a bending beam structure having a meander shape. Furthermore, it is necessary to mount the meander-shaped bending beam structure between two spacers, providing a further disadvantage in that the meander-shaped bending beam structure may be damaged during operation of the position sensor due to mechanical stresses.